In integrated optical circuits, there is often a requirement to re-direct light from an optical waveguide, e.g. from a waveguide formed on the chip to a receiver such as a photodiode, mounted on the chip. A variety of ways of achieving this have been proposed in a variety of types of integrated optical circuits, e.g. by positioning a photodiode within a recess formed in the chip so it receives light emerging from a waveguide on the chip. Many of the known arrangements are however, difficult to fabricate accurately and inexpensively due to the requirement of ensuring accurate positioning and alignment of the various components concerned.
This invention aims to provide a device formed on a silicon-on-insulator chip and which employs features of such a chip and of waveguides formed thereon to assist in the alignment of the components of the device.